extension for computing string similarities and edit distances

The Levenshtein module computes Levenshtein distances, similarity ratios,
generalized medians and set medians of Unicode or non-Unicode strings.
Because it's implemented in C, it's much faster than the corresponding
Python library functions and methods.

The Levenshtein distance is the minimum number of single-character
insertions, deletions, and substitutions to transform one string into
another.

It is useful for spell checking, or fuzzy matching of gettext messages.